109 lines
2.2 KiB
JavaScript
109 lines
2.2 KiB
JavaScript
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var TreeBase = require('./treebase');
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function Node(data) {
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this.data = data;
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this.left = null;
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this.right = null;
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}
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Node.prototype.get_child = function(dir) {
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return dir ? this.right : this.left;
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};
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Node.prototype.set_child = function(dir, val) {
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if(dir) {
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this.right = val;
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}
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else {
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this.left = val;
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}
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};
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function BinTree(comparator) {
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this._root = null;
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this._comparator = comparator;
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this.size = 0;
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}
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BinTree.prototype = new TreeBase();
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// returns true if inserted, false if duplicate
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BinTree.prototype.insert = function(data) {
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if(this._root === null) {
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// empty tree
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this._root = new Node(data);
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this.size++;
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return true;
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}
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var dir = 0;
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// setup
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var p = null; // parent
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var node = this._root;
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// search down
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while(true) {
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if(node === null) {
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// insert new node at the bottom
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node = new Node(data);
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p.set_child(dir, node);
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ret = true;
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this.size++;
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return true;
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}
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// stop if found
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if(this._comparator(node.data, data) === 0) {
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return false;
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}
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dir = this._comparator(node.data, data) < 0;
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// update helpers
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p = node;
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node = node.get_child(dir);
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}
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};
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// returns true if removed, false if not found
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BinTree.prototype.remove = function(data) {
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if(this._root === null) {
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return false;
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}
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var head = new Node(undefined); // fake tree root
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var node = head;
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node.right = this._root;
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var p = null; // parent
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var found = null; // found item
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var dir = 1;
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while(node.get_child(dir) !== null) {
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p = node;
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node = node.get_child(dir);
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var cmp = this._comparator(data, node.data);
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dir = cmp > 0;
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if(cmp === 0) {
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found = node;
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}
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}
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if(found !== null) {
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found.data = node.data;
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p.set_child(p.right === node, node.get_child(node.left === null));
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this._root = head.right;
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this.size--;
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return true;
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}
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else {
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return false;
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}
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};
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module.exports = BinTree;
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